Walking Directions to CDP from MBTA - Alewife Station, the last station outbound on the Red Line:

Exit Alewife Station onto the divided street perpendicular to Cambridge Park Drive and cross the divided street to the opposite side (in front of parking garage).
Turn right and walk up the sidewalk along the exit ramp from Rte. 2. (As you face the ramp, you should be on the left side of the road.)
Proceed up the ramp and turn left at the first street on the left, Acorn Park Drive.
Cross to the right side of the street and continue past two buildings along the sidewalk.
100 Acorn Park Drive will be on your right.